The Google Reader blog announced you can now track changes to any web page, even the ones without RSS feeds.
How does this come in handy? Well, let’s say you want to track when Google changes their webmaster guidelines. All you do is copy the URL into Google Reader and click on “create a feed.” Google Reader will then periodically visit the page and publish any significant changes it finds as items in a custom feed created just for that page.
Here is a picture:
After you click “create a feed” Google will label the item as “a Google-created feed.”
This can come in handy for SEOs, webmasters, searchers, researchers, news writers, savvy shoppers and many more.
Technically, this cannot track every web page out there. You can opt out your pages from this by blocking Googlebot from indexing it via your robots.txt file or by using the noarchive tag, as specified here <meta name=”googlebot” content=”noarchive”>.